P0504

DTC P0504 BRAKE SWITCH "A"/"B" CORRELATION*

*: Only for sequential manual transmission vehicle.

CIRCUIT DESCRIPTION

DTC Detection Condition:

In addition to turning on the stop lights, the stop light switch signals are used for a variety of engine, transmission, and suspension functions as well as being an input for diagnostic checks. It is important that the switch operates properly, therefore this switch is designed with two complementary signal outputs: STP and ST1-. The ECM analyzes these signal outputs to detect malfunctions in the stop light switch.

HINT: The normal condition of the switches are shown.

Wiring Condition:

INSPECTION PROCEDURE

HINT: Read freeze frame data using the hand-held tester or the OBD II scan tool. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, freeze frame data can help determine if the vehicle was running or stopped, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, as well as other data from the time when a malfunction occurred.

Step 1 - 3:

Step 4:

Step 5:

Hand-held tester

Step 1:

Step 2 - 3:

Step 4:

Step 5:

OBD II scan tool (excluding hand-held tester)

CHECK FOR INTERMITTENT PROBLEMS

Hand-held tester only:
Inspect the vehicle's ECM using check mode. Intermittent problems are easier to detect when the ECM is in check mode. In check mode, the ECM uses 1 trip detection logic, which has a higher sensitivity to malfunctions than normal mode (default), which uses 2 trip detection logic.

a. Clear the DTCs.
b. Change to check mode.
c. Perform a simulation test.
d. Check the connector and terminal.
e. Wiggle the harness and connector.